Modern aircraft often use decoy flares to defeat infrared-guided weapons. Typically, decoy flares are deployed in flight by ejecting the flare from a tube and then igniting the flare, which emits electromagnetic radiation. The infrared-guided weapon can lock on and track the decoy flare and/or the heat source of the aircraft can be masked by the flare, providing the aircraft with an opportunity to elude the weapon.
FIG. 1 is a partially schematic cut-away view of a conventional flare 1 and a deployment tube 2 illustrating a system for igniting the flare 1, in accordance with the prior art. In FIG. 1, a bore rider system 4 is used to ignite the flare 1 after the flare 1 leaves the deployment tube 2. The bore rider system 4 has a compartment 10 attached to the flare grain 62. The compartment 10 has a first section 10a and second section 10b. The first section 10a has a first opening 12 and the second section 10b has a second opening 11. A flammable material 20 is coupled to a bore rider 50 that has a depressed position and an extended position. As long as the flare 1 is in the deployment tube 2, the bore rider 50 remains in the depressed position and the flammable material 20 remains in the first section 10a of the compartment 10.
When an expulsion charge 5 is fired, hot expanding gases propel the flare 1 out of the deployment tube 2 and penetrate the first section 10a of the housing 10, igniting the flammable material 20. As the flare 1 leaves the deployment tube 2 (shown by phantom lines), the bore rider is no longer held in the depressed position and a spring 55 moves the flammable material 20 from the first section 10a of the compartment 10 to the second section 10b. In the second section 10b, the flammable material 20 ignites the flare grain, which burns and emits electromagnetic radiation.
A problem with conventional decoy flares is that they can ignite prematurely and/or malfunction so that the flare grain ignites and burns in the deployment tube. For example, combustion can prematurely migrate from the first section of the compartment to the second section and ignite the flare grain before the flare leaves the deployment tube. Additionally, if the flammable material in the compartment ignites before deployment of the flare is commanded, it can cause the flare grain to ignite and burn while the flare is in the deployment tube. Because the deployment tube is not intended to house a burning flare, these conditions can be hazardous to both the aircraft and associated personnel.